Network relay adjusting device



May 7, 1940. w. K. SONNEMANN NETWORK RELAY ADJUSTING DEVICE Filed Jan.9. 1937 INVENTOR MY/iam 5027272277027.

WITNESSES: wM/M (9 W NEY Patented May 7, 1940 UNITED STATES PATENTOFFICE NETWORK RELAY ADJUSTING DEVICE of Pennsylvania ApplicationJanuary 9, 1937, Serial No. 119,806

4 Claims.

My invention relates to alternating-current induction type protectivedevices and particularly to an improved induction-drum network relay ofthe general type disclosed in U. S. Patent No. 2,013,836, grantedSeptember 10, 1935, to John S. Parsons and assigned to WestinghouseElectric & Manufacturing Company.

In the aforesaid Parsons patent, there is disclosed a three-phaseinduction type power directional relay having its magnetic core arrangedas a central group of three symmetrically disposed potential magnets,surrounded by an outer group of three symmetrically disposed current andphasing magnets. The secondary induction element is in the form of aconducting drum, rotatably mounted on the common axis of symmetry of thetwo groups of magnets, and having its cylindrical portion disposed inthe air gaps between the two groups of magnets in order to produce exactquadrature of the potential and current flux, lag loops of copper, orother conducting material, are mounted on the potential magnets.Overvoltage adjustment, for phasing operations, is made by means of asecond group of copper lag loops movably mounted in the air gaps betwenthe potential magnets and the induction drum.

Although the relay described in the abovementioned Parsons patent iscompact in dimensions and provides high torque with satisfactoryoperating characteristics, it is difficult to manufacture and adjustbecause of the extreme accuracy required in positioning the currentmagnets. A displacement of the current magnets of only a few thousandthsof an inch from the position of symmetry opposite the potential magnets,produces an undesirable distortion of the relay characteristics becauseof the effect of the lag loops upon the current magnet flux.

It is an object of my invention to provide a novel network relay of thetype indicated above, which will have characteristics substantially freefrom distortion caused by displacement of the current and phasingmagnets.

A further object of my invention is to provide a novel lag adjustment,suitable for application to induction type protective devices which respond to a second degree electrical quantity, such as power.

Another object of my invention is to provide a novel network relay inwhich a single lag loop serves to produce quadrature relationship ofpotential and current flux and also serves as an overvoltage adjuster.

Other objects of my invention willbecome evident from the followingdetailed description, taken in conjunction with the accompanyingdrawing, in which Figure 1 is a fragmentary plan view, with parts brokenaway, showing one element of an induction-drum relay embodying myinvention;

Fig. 2 is a sectional View on the line II-II of Fig. 1; and

Fig. 3 is an enlarged plan view of a fastening collar used in the relayelement shown in Figs. 1 and 2.

Referring to Figs. 1 and 2 in detail, the relay is provided with a metalbase plate I, which serves as support for the magnets and moving parts.A block 2 of steel or other suitable material is secured to the baseplate I by means of suitable machine screws 3 and 4, which pass throughholes drilled in the base plate I. The hole 5 for the machine screw 4,is of considerably greater diameter than the latter, in order to permitadjustment of the position of the block 2 in a manner to be hereinafterexplained.

A fiat circular washer 6 and a lock washer I are provided between thehead of the screw 4 and the base plate I for locking the block 2 in anyposition to which it may be adjusted. A pair of metal pins 8 are securedto the steel block 2, in parallel relationship, near the base plate I.The pins 8 lie on either side of a pin portion 9 of an eccentric memberID. The eccentric member I is preferably machined as a single piece ofmetal, having a fillister head portion II and a cylindrical bearingsurface journaled in the base plate I. The eccentric member I0 is heldin rotatable relationship in the base plate I by means of a metal collarI2, an enlarged plan view of which is shown in Fig. 3.

A current and phasing magnet I3 is secured to the block 2 by means ofsuitable machine screws I4. The current and phasing magnet I3 comprisesa C-shaped assembly of laminations I5, of

suitable magnetic material, upon which is mounted a pair of currentcoils I6 and a pair of phasing coils IT,

The assembly of laminations I is so shaped as to provide an arcuateinner surface substantially concentric with the axis of a shaft I 8,upon which a cup-shaped. aluminum drum I9 is mounted. The drum I9 servesas the relay secondary element and is mechanically connected to suitablecontact members (not shown) which serve tocomplete a closing circuit forthe network circuit breaker in one position of the drum I9 and tocomplete a tripping circuit for the breaker upon rotation of the drum I9in the opposite direction in a well known manner. A spring 20 isprovided for biasing the drum l9 in .the closing direction, as indicatedby the arrow 2|.

A potential magnet 22 is mounted within the drum it, in a position tocooperate with the current and phasing magnet l3. The potential magnet22 is of substantially E-shape, having a central salient pole 23, uponwhich a potential coil 24 is mounted. The magnetic circuit of thepotential magnet 22 is partially completed by two return branches 25.The outer surfaces of the salient pole 23 and return branches 25 aresubstantially arcuate in form and concentric with the axis of the shaft8.

The free ends of the C-shaped assembly l5 serve as polar projections toproduce a rotating field, in cooperation with the salient pole 23, andthe assembly l5 as a whole serves as a magnetic member to complete themagnetic circuit of the potential magnet 22.

The inner arcuate surface of the current and phasing magnet i3 isrecessed to receive a lag loop 265, of suitable conducting material suchas copper, shown as comprising two O-shaped laminations encompassingpart of both open branches of the C-shaped assembly !5. The lag loop 26is substantially symmetrically disposed with reference to the salientpole 23 of the potential magnet 22.

Although only one relay element, consisting of one potential magnet 22and one current and phasing magnet It, has been shown, it will beunderstood that the complete relay includes three such elements,disposed in symmetrical relationship about the axis of shaft l8. Variousparts of a network relay, themselves well known in the art, but notnecessary to an understanding of the invention, have for simplicity beenomitted. Examples of such parts are the relay casing, the connectionblock used for establishing external connections to the relay parts, andthe reverse power adjusting spring, which is used to provide anadjustable torque opposing operation of the relay movable assembly totripping position. Such parts are illustrated and described in variousprior art publications such as the United States patent to John S.Parsons, No. 1,893,179, issued January 1933, and assigned to theWestinghouse Electric 8; Manufacturing Company.

The operation of the apparatus shown in Figs. 1 and 2 may be set forthas follows: Referring to Fig. 1, it will be noted that the iron parts ofthe current and phasing magnet l3 and the potential magnet 22 provide adivided magnetic circuit for the potential flux which traverses thesalient pole .23. If the C-shaped assembly I?) is symmetrically disposedwith reference to the potential magnet 22, as shown, the magneticcircuit is symmetrically divided so that the magnetic effects producedon one side of the magnetic circuit are duplicated on the other side.

Considering one-half of the magnetic circuit, such as the right handhalf, part of the magnetic flux generated in the salient pole 2-?follows a magnetic path interlinking the lag loop 26 and traversing theinduction drum l9, as indicated by the broken line 2?. Another part ofthe flux produced by the salient pole 23 traverses the induction drum l9but follows a leakage path clear of the lag loop 26, as indicated by thebroken line 28.

As the flux which interlinks the lag loop 25 is lagged in phase becauseof the wellknown action of a shading coil, the equivalent of ashaded-pole induction motor is present, and torque is produced becauseof the action of the potential magnet 22 alone, even though the currentand phasing magnet l3 is deenergized. The torque produced on the rightside of the magnetic circuit in this way is balanced by an equal andopposite torque produced on the left side of the magnetic circuit.

However, if the entire current and phasing magnet I3 is rotated slightlyin the clockwise direction as seen in Fig. 1 about the machine screw 3as a pivot, the air gaps in the right side of the magnetic circuit arereduced in length, whereas the corresponding air gaps in the left sideof the magnetic circuit remain of approximately their original length.Because of the reduction of air gap length on the right side of themagnetic circuit, the various flux components on the right side areincreased in magnitude, and the torque produced by the right side of themagnetic circuit predominates. An unbalanced torque is accordinglyproduced, and the induction drum would turn if its motion wereunopposed.

The direction of the unbalanced torque produced in this way depends uponthe relative impedance phase angle of the electric circuit of the lagloop 26 as compared with effective impedance phase angle of the eddycurrent secondary circuit in the induction drum Hi. I have found thatfor a network relay of the type described, with the lag loop 26 designedto produce a watt characteristic during directional operation, theunbalanced torque tends to rotate the drum l9 from the side having thelonger air gap toward the side having the shorter air gap.

The unbalanced torque produced by the potential magnet 22 alone, in themanner described above, is used to overcome the bias of the spring 29and provide a bias tending to prevent rotation of the drum I9 in theclosing direction, as indicated by the arrow 2|.

As the salient potential pole 23 is angularly displaced from the openends of the C-shaped assembly I5, operating torque proportional to thevector product of current in the potential coil 24 and current in eitherthe current coils l6 or the phasing coils I1, is produced in the usualmanner. It will be understood that the current coils 16 are connected insuch relative direction as to produce additive magnetomotive forcesacting around the C-shaped core, and the phasing coils are similarlyconnected.

In order to adjust the magnitude of unbal anced torque produced by thepotential magnet 22 alone, the machine screw 4 is rotated to re leasethe block 2, and the eccentric member ID is then turned by means of ascrew driver, until the desired value of torque is produced. machinescrew 4 is then tightened to maintain the adjustment.

I do not intend that the present invention shall be restricted to thespecific structural details, arrangement of parts or circuit connectionsherein set forth, as various modifications thereof may be effectedwithout departing from the spirit and scope of my invention. I desire,therefore, that only such limitations shall be imposed as are indicatedin the appended claims.

I claim as my invention:

1. In an alternating-current power-responsive network protective device,a rotatable drum having a conducting skirt portion, a potential magnetwithin said drum, said potential magnet hav- The ing a salient poleadjacent said skirt portion, a

current magnet outside of said drum, said cur rent magnet having a pairof polar projections erence to said salient pole along the periphery ofsaid skirt portion, a short-circuited coil mounted on said currentmagnet in a position to divide the effective pole area of each of saidpolar projections into two parts and to enclose one of said parts foreach of said polar projections, and means for angularly adjusting saidcurrent mag net to bring one of said polar projections into closerproximity to said skirt portion than the other of said polarprojections. r

2. In an alternating current relay, a rotatable armature, anelectromagnet having a salient pole disposed on one side of saidarmature, a magnetic member having a short-circuited coil thereon andmounted on the other side of said armature, said electromagnet andmagnetic member and the air gap between them through which the armaturemoves constituting a divided substantially symmetrical magnetic circuithaving a common branch in said salient pole, a lagged return branchtraversing said armature and said magnetic member through saidshort-circuited coil, and a leakage return branch traversing saidarmature and said magnetic member external to said short-circuited coil,and means for adjusting the position of said magnetic member withrespect to said salient pole to alter the effective air-gap length ofone division of each of said divided branches, said magnetic memberbeing an integral structure angularly movable as a unit with respect tothe axis of said salient pole.

3. In an alternating-current induction-type device, a movable conductingarmature, an electromagnet having a salient pole on one side of saidarmature, a magnetic member on the other side of said armature having apair of salient projections symmetrically disposed with respect to saidsalient pole and located along the line of movement of said armature,said electromagnet and magnetic member being proportional to define adivided magnetic circuit through said armature with branches eachincluding one of said salient projections, means for lagging part of theflux of both of said magnetic branches comprising a short-circuited coilmounted on said magnetic member substantially opposite said salientpole, said short-circuited coil being positioned to divide the effectivepole area of each of said salient projections into two parts disposed insequential relationship along the path of movement of said armature andto enclose the part, individual to each of said salient projections,closest to the axis of said salient pole, and means for adjustablymoving said magnetic member as a unit angularly with respect to theadjacent surface of said armature to increase the effective air-gaplength of one of said magnetic branch circuits with respect to theother.

4. In an alternating-current induction-type device, a rotatable drumhaving a conducting skirtportion, an electromagnet including asalient'pole on one side of said skirt portion, a magnetic member havinga pair of salient projections on the other side of said skirt portion,said salient projections being substantially symmetrically disposed withrespect to said salient.

pole along the periphery of said skirt portion and spaced therefrom todefine an eifective airgap through which said armature may rotate, saidelectromagnet and magnetic member being proportional to define a dividedmagnetic circuit through said armature with branches each including oneof said salient projections, means for lagging part of the flux of bothof said magnetic branches comprising a short-circuited coil mounted onsaid salient projections substantially opposite said salient pole, saidshortcircuited coil being positioned to divide the effective pole areaof each of said salient projections into two parts disposed insequential relationship along the path of movement of said skirtportion, and to enclose the part, individual to each of said salientprojections, closest to the axis of said salient pole, and means foradjustably moving said magnetic member as a unit angularly with respectto the adjacent surface of said armature to increase the effectiveair-gap length of one of said magnetic branch circuits with respect tothe other.

WILLIAM K. SONNEMANN.

